UnitedHealthcare plans to join New Jersey’s Obamacare health insurance exchange and sell policies that would go into effect in 2015, the company said Monday.

The move would give consumers more choices in a state whose insurance premiums are among the nation’s highest.

“Just having another (insurer) could make it cheaper for people,” said Beatriz Patino, health exchange coordinator for Ocean Health Initiatives Inc., a Toms River-based health center that helped consumers sign up for insurance through the exchange. “That’s what I hope for our next open enrollment.”

Minneapolis-based UnitedHealthcare previously sold insurance in New Jersey, but not on the exchange, the marketplace set up by the Affordable Care Act for consumers who aren’t insured through employer plans.

New Jersey is one of 36 states nationwide that opted to use the federal exchange. A report released last week found New Jerseyans buying insurance on the exchange paid an average of $465 a month if they did not qualify for tax credits and $148 a month if they did. By comparison, the average premium for all states using the federal exchange was $346, or $82 after tax credits.

Observers said it reflected New Jersey’s high cost of living, but they also wondered if the lack of competition played a part. Just three insurers — AmeriHealth NJ, Health Republic of New Jersey and Horizon Blue Cross Blue Shield of New Jersey — sold plans on New Jersey’s exchange last year. Meanwhile, 16 insurers in New York sold plans on its exchange.

There was little difference in average prices between the two states. But New Yorkers had far more choices, and the prices of the insurance companies’ policies varied widely.